In the United States, safety regulations require that lawnmowers must be equipped with some type of handle-mounted “dead man” control, an operator presence control device that stops the blade within a brief time (e.g., 3 seconds) after the operator presence control is released. Common systems used for this purpose include zone brake systems and blade brake clutches.
Zone brake systems stop the engine and blade in a short period after the operator releases a zone brake control device, either intentionally or inadvertently. In this regard, movement of the zone brake control to an operating position can release the engine and blade brake and also energize the engine's ignition system. Conversely, movement of the zone brake control to a non-operating or braking position can brake the engine and blade and also deenergize the engine ignition system, stopping the rotating blade within a few seconds. In contrast, a mower equipped with a blade brake clutch can similarly be operated to brake or release the rotating cutting blade, but the engine need not be deenergized.
In either system, one common kind of operator presence control device is a rotatable bail (e.g., a steel wireform bar or lever) mounted to the handle of the lawnmower. Typically, the operator must rotate the bail and hold it in place against the handle of the lawnmower to put the zone brake system or the blade brake clutch in an operable position (i.e., blade and engine on). Although this kind of device provides a valuable (and required) safety feature, such rotating bails can be considered unsightly and uncomfortable to use.